<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>请用循环计算出 1+2+3+4+5+...+100   的值</title>
    <script>
        var sum = 0;
        for(var i = 1; i <= 100; i++){
            sum +=i;
        }
        console.log(sum)
        alert("1+2+3+4+5+...+100 " + sum);
    </script>
</head>
<body>
    
</body>
</html>